US Bridges

T 21 over Big Cottonwood River

FairPosted for load

Lyon County, Minnesota · 2.7 MI S of JCT Csah 2 · Structure no. L2953

Built
1974
51 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
25 ft
1 main span
Daily traffic
21
1992 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

T 21 over Big Cottonwood River is a wood or timber stringer/multi-beam or girder carrying T 21 over Big Cottonwood River in Lyon County, Minnesota. It was built in 1974, so it is 51 years old, older than the Minnesota average of 38.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 21 vehicles a day, projected to reach 21 by 2029. The structure is 25 ft (7.5 m) long and 26 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesT 21
CrossesBig Cottonwood River
Location2.7 MI S of JCT Csah 2
RouteCounty Highway 21
CountyLyon County
StateMinnesota
Coordinates44.273, -95.77516
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourScour critical; extensive scour has occurred
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating46.6 US tons
Inventory rating32.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadUnknown
Structure length25 ft (7.5 m)
Longest span22 ft (6.8 m)
Deck width26 ft (7.8 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21 (1992)
Projected traffic21 by 2029
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$600 million (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was T 21 over Big Cottonwood River built?

It was built in 1974, making it 51 years old in 2025.

What condition is T 21 over Big Cottonwood River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2023.

How much traffic does T 21 over Big Cottonwood River carry?

About 21 vehicles per day (1992 count).

How long is T 21 over Big Cottonwood River?

The structure is 25 ft (7.5 m) long with a longest span of 22 ft (6.8 m) and a deck 26 ft wide.

Who owns T 21 over Big Cottonwood River?

It is owned by the Town or Township Highway Agency.